#include <QCoreApplication>
#include <iostream>
using namespace std;

int main()
{
  int A,B,R = 0;
  cout<<"Vvedite A: ";
 cin>>A;
 cout<<"Vvedete B: ";
  cin>>B;
  R = 1;
  if (A<B)
  {
    for (;A <= B;A++)
    {
      R=R*A;
    }
   cout<<"\n"<<R;
  }

  return 0;
}
